Add a missing COPYING file.
Add a missing COPYING file.

Patch by Stephen Gallagher.
Reviewed at http://reviews.reviewboard.org/r/1384/

Khan/rbtools,bcelary/rbtools,davidt/rbtools,reviewboard/rbtools,haosdent/rbtools,beol/rbtools,davidt/rbtools,reviewboard/rbtools,blair/pkg-rbtools,halvorlu/rbtools,halvorlu/rbtools,1tush/rbtools,clach04/rbtools,davidt/rbtools,clach04/rbtools_0.4.1,halvorlu/rbtools,clach04/old_rbtools_0.3.2,datjwu/rbtools,haosdent/rbtools,datjwu/rbtools,beol/rbtools,haosdent/rbtools,Khan/rbtools,datjwu/rbtools,reviewboard/rbtools,beol/rbtools